Description
Analysis of MASS SPEC, IR and NMR Data and Presentation
For each experiment, MS, IR and NMR, create tables in your notebook, summarizing the primary and derived
data from the spectra. Your tables will contain supportive evidence from the spectra for various
structural possibilities. Where possible, annotate the spectra using the examples provided as a guide. Depending
upon the difficulty of your spectra, you may or may not be able to narrow your identification to a single probable
compound. Your grade will be based upon your interpretation of the data, and not solely upon whether you
correctly identify the compound. No one experimental technique will probably solve the structure completely. Also,
it may not be possible to abstract all of the potential data a spectral technique could yield. Try to be objective and
not prematurely jump to conclusions too quickly about your unknown structures from any one set of data.
The best approached is to look at the data from each experimental technique independently. Use the
Functional Group List (last page), and try to place each functional group in to one of these three categories:
1. Functional groups that you are absolutely certain are present (Y),
2. Functional groups that you are absolutely certain are not present (N).
3. Functional groups that you are less certain are present (?).
The molecular weight from the mass spectrum, major fragmentation ions and the IR spectrum should help solve
the status of functional groups that are in category 3. Work on reducing category 3 items until they change to
either category 1 or 2 (that is either present or definitely not present). Finally, integrate the data from the three
experimental methods to look for consistencies or inconsistencies, and then postulate possible molecular structure
or structures that would fit all of your data. You can consult the CRC Handbook (the internet, or Merck Manual)
for physical properties (color, odor, physical state, etc.) of your postulated structures to see if they are consistent
with your unknown.
Reporting Your Results- MS, IR & NMR Oral Presentation
What you want to do is present the data in an easy to follow way that leads your audience to the same conclusion
as to the identity of your unknown compound. This means you first provide the evidence and then deduce from it
structural data about your compound. Make your presentation brief. Use succinct statements that are supported
by the experimental data. Don’t make any of your slide overly wordy or complex.
The presentation must include relevant spectra and tables to support your conclusions. The MS, IR, and NMR
data analyses and interpretations all are considered in your final grade.
Order of Presentation
It is up to you to decide how you want to present your argument for compound identification. Think of yourself as
the courtroom lawyer who is presenting his case to a jury- your audience.
Here is my suggestion:
1. First slide: your name, title of project, class, unknown number and date.
2. Identify any physical properties (solid, liquid, color, odor, volatility, etc.)
3. Pick one of the methods (IR, NMR or Mass Spec) and discuss it fully. Refer to the Criteria for Grading sheet
that lists the specific items you must mention in your presentation. Remember to list the functional groups that
are present, definitely not present, and those that might be present (Categories 1,2 and 3, respectively). Finally
summarize your results for this method of analysis.
4. Continue to use the same format to discuss the other two methods of analysis.
5. Now discuss your analysis of all three sets of data together. Show how the data from the three methods are
consistent (or in what way inconsistent) and what structure(s) you propose that fit the data best.
6. Show the structure of the molecule you propose and briefly go over the key data you collected that lead you to
this conclusion. Think about what questions you might be asked about the data and how you will respond to
them.
Final Comments
It is not necessary for you to provide a correct chemical structure to receive nearly full credit on this project. The
quality of the interpretation of your MS, IR and NMR spectra will have the greatest effect on your grade. If you
identify the unknown compound correctly but do not provide adequate spectra evidence to support your
conclusions, your grade will suffer. Your explanation must defend all the functional groups you have selected.
Purchase answer to see full
attachment